1 /*
2 * AC-3 Audio Decoder
3 * This code was developed as part of Google Summer of Code 2006.
4 * E-AC-3 support was added as part of Google Summer of Code 2007.
5 *
6 * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com)
7 * Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
8 * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
9 *
10 * This file is part of FFmpeg.
11 *
12 * FFmpeg is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU Lesser General Public
14 * License as published by the Free Software Foundation; either
15 * version 2.1 of the License, or (at your option) any later version.
16 *
17 * FFmpeg is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Lesser General Public License for more details.
21 *
22 * You should have received a copy of the GNU Lesser General Public
23 * License along with FFmpeg; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 */
26
27 #include <stdio.h>
28 #include <stddef.h>
29 #include <math.h>
30 #include <string.h>
31
32 #include "libavutil/channel_layout.h"
33 #include "libavutil/crc.h"
34 #include "libavutil/downmix_info.h"
35 #include "libavutil/opt.h"
36 #include "bswapdsp.h"
37 #include "internal.h"
38 #include "aac_ac3_parser.h"
39 #include "ac3_parser_internal.h"
40 #include "ac3dec.h"
41 #include "ac3dec_data.h"
42 #include "kbdwin.h"
43
44 /**
45 * table for ungrouping 3 values in 7 bits.
46 * used for exponents and bap=2 mantissas
47 */
48 static uint8_t ungroup_3_in_7_bits_tab[128][3];
49
50 /** tables for ungrouping mantissas */
51 static int b1_mantissas[32][3];
52 static int b2_mantissas[128][3];
53 static int b3_mantissas[8];
54 static int b4_mantissas[128][2];
55 static int b5_mantissas[16];
56
57 /**
58 * Quantization table: levels for symmetric. bits for asymmetric.
59 * reference: Table 7.18 Mapping of bap to Quantizer
60 */
61 static const uint8_t quantization_tab[16] = {
62 0, 3, 5, 7, 11, 15,
63 5, 6, 7, 8, 9, 10, 11, 12, 14, 16
64 };
65
66 #if (!USE_FIXED)
67 /** dynamic range table. converts codes to scale factors. */
68 static float dynamic_range_tab[256];
69 float ff_ac3_heavy_dynamic_range_tab[256];
70 #endif
71
72 /** Adjustments in dB gain */
73 static const float gain_levels[9] = {
74 LEVEL_PLUS_3DB,
75 LEVEL_PLUS_1POINT5DB,
76 LEVEL_ONE,
77 LEVEL_MINUS_1POINT5DB,
78 LEVEL_MINUS_3DB,
79 LEVEL_MINUS_4POINT5DB,
80 LEVEL_MINUS_6DB,
81 LEVEL_ZERO,
82 LEVEL_MINUS_9DB
83 };
84
85 /** Adjustments in dB gain (LFE, +10 to -21 dB) */
86 static const float gain_levels_lfe[32] = {
87 3.162275, 2.818382, 2.511886, 2.238719, 1.995261, 1.778278, 1.584893,
88 1.412536, 1.258924, 1.122018, 1.000000, 0.891251, 0.794328, 0.707946,
89 0.630957, 0.562341, 0.501187, 0.446683, 0.398107, 0.354813, 0.316227,
90 0.281838, 0.251188, 0.223872, 0.199526, 0.177828, 0.158489, 0.141253,
91 0.125892, 0.112201, 0.100000, 0.089125
92 };
93
94 /**
95 * Table for default stereo downmixing coefficients
96 * reference: Section 7.8.2 Downmixing Into Two Channels
97 */
98 static const uint8_t ac3_default_coeffs[8][5][2] = {
99 { { 2, 7 }, { 7, 2 }, },
100 { { 4, 4 }, },
101 { { 2, 7 }, { 7, 2 }, },
102 { { 2, 7 }, { 5, 5 }, { 7, 2 }, },
103 { { 2, 7 }, { 7, 2 }, { 6, 6 }, },
104 { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 }, },
105 { { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
106 { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
107 };
108
109 /**
110 * Symmetrical Dequantization
111 * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
112 * Tables 7.19 to 7.23
113 */
114 static inline int
symmetric_dequant(int code,int levels)115 symmetric_dequant(int code, int levels)
116 {
117 return ((code - (levels >> 1)) * (1 << 24)) / levels;
118 }
119
120 /*
121 * Initialize tables at runtime.
122 */
ac3_tables_init(void)123 static av_cold void ac3_tables_init(void)
124 {
125 int i;
126
127 /* generate table for ungrouping 3 values in 7 bits
128 reference: Section 7.1.3 Exponent Decoding */
129 for (i = 0; i < 128; i++) {
130 ungroup_3_in_7_bits_tab[i][0] = i / 25;
131 ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
132 ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5;
133 }
134
135 /* generate grouped mantissa tables
136 reference: Section 7.3.5 Ungrouping of Mantissas */
137 for (i = 0; i < 32; i++) {
138 /* bap=1 mantissas */
139 b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
140 b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
141 b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
142 }
143 for (i = 0; i < 128; i++) {
144 /* bap=2 mantissas */
145 b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5);
146 b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5);
147 b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5);
148
149 /* bap=4 mantissas */
150 b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
151 b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
152 }
153 /* generate ungrouped mantissa tables
154 reference: Tables 7.21 and 7.23 */
155 for (i = 0; i < 7; i++) {
156 /* bap=3 mantissas */
157 b3_mantissas[i] = symmetric_dequant(i, 7);
158 }
159 for (i = 0; i < 15; i++) {
160 /* bap=5 mantissas */
161 b5_mantissas[i] = symmetric_dequant(i, 15);
162 }
163
164 #if (!USE_FIXED)
165 /* generate dynamic range table
166 reference: Section 7.7.1 Dynamic Range Control */
167 for (i = 0; i < 256; i++) {
168 int v = (i >> 5) - ((i >> 7) << 3) - 5;
169 dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
170 }
171
172 /* generate compr dynamic range table
173 reference: Section 7.7.2 Heavy Compression */
174 for (i = 0; i < 256; i++) {
175 int v = (i >> 4) - ((i >> 7) << 4) - 4;
176 ff_ac3_heavy_dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0xF) | 0x10);
177 }
178 #endif
179 }
180
181 /**
182 * AVCodec initialization
183 */
ac3_decode_init(AVCodecContext * avctx)184 static av_cold int ac3_decode_init(AVCodecContext *avctx)
185 {
186 AC3DecodeContext *s = avctx->priv_data;
187 int i;
188
189 s->avctx = avctx;
190
191 ac3_tables_init();
192 ff_mdct_init(&s->imdct_256, 8, 1, 1.0);
193 ff_mdct_init(&s->imdct_512, 9, 1, 1.0);
194 AC3_RENAME(ff_kbd_window_init)(s->window, 5.0, 256);
195 ff_bswapdsp_init(&s->bdsp);
196
197 #if (USE_FIXED)
198 s->fdsp = avpriv_alloc_fixed_dsp(avctx->flags & AV_CODEC_FLAG_BITEXACT);
199 #else
200 s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
201 ff_fmt_convert_init(&s->fmt_conv, avctx);
202 #endif
203
204 ff_ac3dsp_init(&s->ac3dsp, avctx->flags & AV_CODEC_FLAG_BITEXACT);
205 av_lfg_init(&s->dith_state, 0);
206
207 if (USE_FIXED)
208 avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
209 else
210 avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
211
212 /* allow downmixing to stereo or mono */
213 if (avctx->channels > 1 &&
214 avctx->request_channel_layout == AV_CH_LAYOUT_MONO)
215 avctx->channels = 1;
216 else if (avctx->channels > 2 &&
217 avctx->request_channel_layout == AV_CH_LAYOUT_STEREO)
218 avctx->channels = 2;
219 s->downmixed = 1;
220
221 for (i = 0; i < AC3_MAX_CHANNELS; i++) {
222 s->xcfptr[i] = s->transform_coeffs[i];
223 s->dlyptr[i] = s->delay[i];
224 }
225
226 return 0;
227 }
228
229 /**
230 * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
231 * GetBitContext within AC3DecodeContext must point to
232 * the start of the synchronized AC-3 bitstream.
233 */
ac3_parse_header(AC3DecodeContext * s)234 static int ac3_parse_header(AC3DecodeContext *s)
235 {
236 GetBitContext *gbc = &s->gbc;
237 int i;
238
239 /* read the rest of the bsi. read twice for dual mono mode. */
240 i = !s->channel_mode;
241 do {
242 s->dialog_normalization[(!s->channel_mode)-i] = -get_bits(gbc, 5);
243 if (s->dialog_normalization[(!s->channel_mode)-i] == 0) {
244 s->dialog_normalization[(!s->channel_mode)-i] = -31;
245 }
246 if (s->target_level != 0) {
247 s->level_gain[(!s->channel_mode)-i] = powf(2.0f,
248 (float)(s->target_level -
249 s->dialog_normalization[(!s->channel_mode)-i])/6.0f);
250 }
251 if (s->compression_exists[(!s->channel_mode)-i] = get_bits1(gbc)) {
252 s->heavy_dynamic_range[(!s->channel_mode)-i] =
253 AC3_HEAVY_RANGE(get_bits(gbc, 8));
254 }
255 if (get_bits1(gbc))
256 skip_bits(gbc, 8); //skip language code
257 if (get_bits1(gbc))
258 skip_bits(gbc, 7); //skip audio production information
259 } while (i--);
260
261 skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
262
263 /* skip the timecodes or parse the Alternate Bit Stream Syntax */
264 if (s->bitstream_id != 6) {
265 if (get_bits1(gbc))
266 skip_bits(gbc, 14); //skip timecode1
267 if (get_bits1(gbc))
268 skip_bits(gbc, 14); //skip timecode2
269 } else {
270 if (get_bits1(gbc)) {
271 s->preferred_downmix = get_bits(gbc, 2);
272 s->center_mix_level_ltrt = get_bits(gbc, 3);
273 s->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7);
274 s->center_mix_level = get_bits(gbc, 3);
275 s->surround_mix_level = av_clip(get_bits(gbc, 3), 3, 7);
276 }
277 if (get_bits1(gbc)) {
278 s->dolby_surround_ex_mode = get_bits(gbc, 2);
279 s->dolby_headphone_mode = get_bits(gbc, 2);
280 skip_bits(gbc, 10); // skip adconvtyp (1), xbsi2 (8), encinfo (1)
281 }
282 }
283
284 /* skip additional bitstream info */
285 if (get_bits1(gbc)) {
286 i = get_bits(gbc, 6);
287 do {
288 skip_bits(gbc, 8);
289 } while (i--);
290 }
291
292 return 0;
293 }
294
295 /**
296 * Common function to parse AC-3 or E-AC-3 frame header
297 */
parse_frame_header(AC3DecodeContext * s)298 static int parse_frame_header(AC3DecodeContext *s)
299 {
300 AC3HeaderInfo hdr;
301 int err;
302
303 err = ff_ac3_parse_header(&s->gbc, &hdr);
304 if (err)
305 return err;
306
307 /* get decoding parameters from header info */
308 s->bit_alloc_params.sr_code = hdr.sr_code;
309 s->bitstream_id = hdr.bitstream_id;
310 s->bitstream_mode = hdr.bitstream_mode;
311 s->channel_mode = hdr.channel_mode;
312 s->lfe_on = hdr.lfe_on;
313 s->bit_alloc_params.sr_shift = hdr.sr_shift;
314 s->sample_rate = hdr.sample_rate;
315 s->bit_rate = hdr.bit_rate;
316 s->channels = hdr.channels;
317 s->fbw_channels = s->channels - s->lfe_on;
318 s->lfe_ch = s->fbw_channels + 1;
319 s->frame_size = hdr.frame_size;
320 s->superframe_size += hdr.frame_size;
321 s->preferred_downmix = AC3_DMIXMOD_NOTINDICATED;
322 s->center_mix_level = hdr.center_mix_level;
323 s->center_mix_level_ltrt = 4; // -3.0dB
324 s->surround_mix_level = hdr.surround_mix_level;
325 s->surround_mix_level_ltrt = 4; // -3.0dB
326 s->lfe_mix_level_exists = 0;
327 s->num_blocks = hdr.num_blocks;
328 s->frame_type = hdr.frame_type;
329 s->substreamid = hdr.substreamid;
330 s->dolby_surround_mode = hdr.dolby_surround_mode;
331 s->dolby_surround_ex_mode = AC3_DSUREXMOD_NOTINDICATED;
332 s->dolby_headphone_mode = AC3_DHEADPHONMOD_NOTINDICATED;
333
334 if (s->lfe_on) {
335 s->start_freq[s->lfe_ch] = 0;
336 s->end_freq[s->lfe_ch] = 7;
337 s->num_exp_groups[s->lfe_ch] = 2;
338 s->channel_in_cpl[s->lfe_ch] = 0;
339 }
340
341 if (s->bitstream_id <= 10) {
342 s->eac3 = 0;
343 s->snr_offset_strategy = 2;
344 s->block_switch_syntax = 1;
345 s->dither_flag_syntax = 1;
346 s->bit_allocation_syntax = 1;
347 s->fast_gain_syntax = 0;
348 s->first_cpl_leak = 0;
349 s->dba_syntax = 1;
350 s->skip_syntax = 1;
351 memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
352 return ac3_parse_header(s);
353 } else if (CONFIG_EAC3_DECODER) {
354 s->eac3 = 1;
355 return ff_eac3_parse_header(s);
356 } else {
357 av_log(s->avctx, AV_LOG_ERROR, "E-AC-3 support not compiled in\n");
358 return AVERROR(ENOSYS);
359 }
360 }
361
362 /**
363 * Set stereo downmixing coefficients based on frame header info.
364 * reference: Section 7.8.2 Downmixing Into Two Channels
365 */
set_downmix_coeffs(AC3DecodeContext * s)366 static int set_downmix_coeffs(AC3DecodeContext *s)
367 {
368 int i;
369 float cmix = gain_levels[s-> center_mix_level];
370 float smix = gain_levels[s->surround_mix_level];
371 float norm0, norm1;
372 float downmix_coeffs[2][AC3_MAX_CHANNELS];
373
374 if (!s->downmix_coeffs[0]) {
375 s->downmix_coeffs[0] = av_malloc_array(2 * AC3_MAX_CHANNELS,
376 sizeof(**s->downmix_coeffs));
377 if (!s->downmix_coeffs[0])
378 return AVERROR(ENOMEM);
379 s->downmix_coeffs[1] = s->downmix_coeffs[0] + AC3_MAX_CHANNELS;
380 }
381
382 for (i = 0; i < s->fbw_channels; i++) {
383 downmix_coeffs[0][i] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
384 downmix_coeffs[1][i] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
385 }
386 if (s->channel_mode > 1 && s->channel_mode & 1) {
387 downmix_coeffs[0][1] = downmix_coeffs[1][1] = cmix;
388 }
389 if (s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
390 int nf = s->channel_mode - 2;
391 downmix_coeffs[0][nf] = downmix_coeffs[1][nf] = smix * LEVEL_MINUS_3DB;
392 }
393 if (s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
394 int nf = s->channel_mode - 4;
395 downmix_coeffs[0][nf] = downmix_coeffs[1][nf+1] = smix;
396 }
397
398 /* renormalize */
399 norm0 = norm1 = 0.0;
400 for (i = 0; i < s->fbw_channels; i++) {
401 norm0 += downmix_coeffs[0][i];
402 norm1 += downmix_coeffs[1][i];
403 }
404 norm0 = 1.0f / norm0;
405 norm1 = 1.0f / norm1;
406 for (i = 0; i < s->fbw_channels; i++) {
407 downmix_coeffs[0][i] *= norm0;
408 downmix_coeffs[1][i] *= norm1;
409 }
410
411 if (s->output_mode == AC3_CHMODE_MONO) {
412 for (i = 0; i < s->fbw_channels; i++)
413 downmix_coeffs[0][i] = (downmix_coeffs[0][i] +
414 downmix_coeffs[1][i]) * LEVEL_MINUS_3DB;
415 }
416 for (i = 0; i < s->fbw_channels; i++) {
417 s->downmix_coeffs[0][i] = FIXR12(downmix_coeffs[0][i]);
418 s->downmix_coeffs[1][i] = FIXR12(downmix_coeffs[1][i]);
419 }
420
421 return 0;
422 }
423
424 /**
425 * Decode the grouped exponents according to exponent strategy.
426 * reference: Section 7.1.3 Exponent Decoding
427 */
decode_exponents(AC3DecodeContext * s,GetBitContext * gbc,int exp_strategy,int ngrps,uint8_t absexp,int8_t * dexps)428 static int decode_exponents(AC3DecodeContext *s,
429 GetBitContext *gbc, int exp_strategy, int ngrps,
430 uint8_t absexp, int8_t *dexps)
431 {
432 int i, j, grp, group_size;
433 int dexp[256];
434 int expacc, prevexp;
435
436 /* unpack groups */
437 group_size = exp_strategy + (exp_strategy == EXP_D45);
438 for (grp = 0, i = 0; grp < ngrps; grp++) {
439 expacc = get_bits(gbc, 7);
440 if (expacc >= 125) {
441 av_log(s->avctx, AV_LOG_ERROR, "expacc %d is out-of-range\n", expacc);
442 return AVERROR_INVALIDDATA;
443 }
444 dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0];
445 dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1];
446 dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2];
447 }
448
449 /* convert to absolute exps and expand groups */
450 prevexp = absexp;
451 for (i = 0, j = 0; i < ngrps * 3; i++) {
452 prevexp += dexp[i] - 2;
453 if (prevexp > 24U) {
454 av_log(s->avctx, AV_LOG_ERROR, "exponent %d is out-of-range\n", prevexp);
455 return AVERROR_INVALIDDATA;
456 }
457 switch (group_size) {
458 case 4: dexps[j++] = prevexp;
459 dexps[j++] = prevexp;
460 case 2: dexps[j++] = prevexp;
461 case 1: dexps[j++] = prevexp;
462 }
463 }
464 return 0;
465 }
466
467 /**
468 * Generate transform coefficients for each coupled channel in the coupling
469 * range using the coupling coefficients and coupling coordinates.
470 * reference: Section 7.4.3 Coupling Coordinate Format
471 */
calc_transform_coeffs_cpl(AC3DecodeContext * s)472 static void calc_transform_coeffs_cpl(AC3DecodeContext *s)
473 {
474 int bin, band, ch;
475
476 bin = s->start_freq[CPL_CH];
477 for (band = 0; band < s->num_cpl_bands; band++) {
478 int band_start = bin;
479 int band_end = bin + s->cpl_band_sizes[band];
480 for (ch = 1; ch <= s->fbw_channels; ch++) {
481 if (s->channel_in_cpl[ch]) {
482 int cpl_coord = s->cpl_coords[ch][band] << 5;
483 for (bin = band_start; bin < band_end; bin++) {
484 s->fixed_coeffs[ch][bin] =
485 MULH(s->fixed_coeffs[CPL_CH][bin] * (1 << 4), cpl_coord);
486 }
487 if (ch == 2 && s->phase_flags[band]) {
488 for (bin = band_start; bin < band_end; bin++)
489 s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin];
490 }
491 }
492 }
493 bin = band_end;
494 }
495 }
496
497 /**
498 * Grouped mantissas for 3-level 5-level and 11-level quantization
499 */
500 typedef struct mant_groups {
501 int b1_mant[2];
502 int b2_mant[2];
503 int b4_mant;
504 int b1;
505 int b2;
506 int b4;
507 } mant_groups;
508
509 /**
510 * Decode the transform coefficients for a particular channel
511 * reference: Section 7.3 Quantization and Decoding of Mantissas
512 */
ac3_decode_transform_coeffs_ch(AC3DecodeContext * s,int ch_index,mant_groups * m)513 static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
514 {
515 int start_freq = s->start_freq[ch_index];
516 int end_freq = s->end_freq[ch_index];
517 uint8_t *baps = s->bap[ch_index];
518 int8_t *exps = s->dexps[ch_index];
519 int32_t *coeffs = s->fixed_coeffs[ch_index];
520 int dither = (ch_index == CPL_CH) || s->dither_flag[ch_index];
521 GetBitContext *gbc = &s->gbc;
522 int freq;
523
524 for (freq = start_freq; freq < end_freq; freq++) {
525 int bap = baps[freq];
526 int mantissa;
527 switch (bap) {
528 case 0:
529 /* random noise with approximate range of -0.707 to 0.707 */
530 if (dither)
531 mantissa = (((av_lfg_get(&s->dith_state)>>8)*181)>>8) - 5931008;
532 else
533 mantissa = 0;
534 break;
535 case 1:
536 if (m->b1) {
537 m->b1--;
538 mantissa = m->b1_mant[m->b1];
539 } else {
540 int bits = get_bits(gbc, 5);
541 mantissa = b1_mantissas[bits][0];
542 m->b1_mant[1] = b1_mantissas[bits][1];
543 m->b1_mant[0] = b1_mantissas[bits][2];
544 m->b1 = 2;
545 }
546 break;
547 case 2:
548 if (m->b2) {
549 m->b2--;
550 mantissa = m->b2_mant[m->b2];
551 } else {
552 int bits = get_bits(gbc, 7);
553 mantissa = b2_mantissas[bits][0];
554 m->b2_mant[1] = b2_mantissas[bits][1];
555 m->b2_mant[0] = b2_mantissas[bits][2];
556 m->b2 = 2;
557 }
558 break;
559 case 3:
560 mantissa = b3_mantissas[get_bits(gbc, 3)];
561 break;
562 case 4:
563 if (m->b4) {
564 m->b4 = 0;
565 mantissa = m->b4_mant;
566 } else {
567 int bits = get_bits(gbc, 7);
568 mantissa = b4_mantissas[bits][0];
569 m->b4_mant = b4_mantissas[bits][1];
570 m->b4 = 1;
571 }
572 break;
573 case 5:
574 mantissa = b5_mantissas[get_bits(gbc, 4)];
575 break;
576 default: /* 6 to 15 */
577 /* Shift mantissa and sign-extend it. */
578 if (bap > 15) {
579 av_log(s->avctx, AV_LOG_ERROR, "bap %d is invalid in plain AC-3\n", bap);
580 bap = 15;
581 }
582 mantissa = (unsigned)get_sbits(gbc, quantization_tab[bap]) << (24 - quantization_tab[bap]);
583 break;
584 }
585 coeffs[freq] = mantissa >> exps[freq];
586 }
587 }
588
589 /**
590 * Remove random dithering from coupling range coefficients with zero-bit
591 * mantissas for coupled channels which do not use dithering.
592 * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
593 */
remove_dithering(AC3DecodeContext * s)594 static void remove_dithering(AC3DecodeContext *s) {
595 int ch, i;
596
597 for (ch = 1; ch <= s->fbw_channels; ch++) {
598 if (!s->dither_flag[ch] && s->channel_in_cpl[ch]) {
599 for (i = s->start_freq[CPL_CH]; i < s->end_freq[CPL_CH]; i++) {
600 if (!s->bap[CPL_CH][i])
601 s->fixed_coeffs[ch][i] = 0;
602 }
603 }
604 }
605 }
606
decode_transform_coeffs_ch(AC3DecodeContext * s,int blk,int ch,mant_groups * m)607 static inline void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk,
608 int ch, mant_groups *m)
609 {
610 if (!s->channel_uses_aht[ch]) {
611 ac3_decode_transform_coeffs_ch(s, ch, m);
612 } else {
613 /* if AHT is used, mantissas for all blocks are encoded in the first
614 block of the frame. */
615 int bin;
616 if (CONFIG_EAC3_DECODER && !blk)
617 ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
618 for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
619 s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
620 }
621 }
622 }
623
624 /**
625 * Decode the transform coefficients.
626 */
decode_transform_coeffs(AC3DecodeContext * s,int blk)627 static inline void decode_transform_coeffs(AC3DecodeContext *s, int blk)
628 {
629 int ch, end;
630 int got_cplchan = 0;
631 mant_groups m;
632
633 m.b1 = m.b2 = m.b4 = 0;
634
635 for (ch = 1; ch <= s->channels; ch++) {
636 /* transform coefficients for full-bandwidth channel */
637 decode_transform_coeffs_ch(s, blk, ch, &m);
638 /* transform coefficients for coupling channel come right after the
639 coefficients for the first coupled channel*/
640 if (s->channel_in_cpl[ch]) {
641 if (!got_cplchan) {
642 decode_transform_coeffs_ch(s, blk, CPL_CH, &m);
643 calc_transform_coeffs_cpl(s);
644 got_cplchan = 1;
645 }
646 end = s->end_freq[CPL_CH];
647 } else {
648 end = s->end_freq[ch];
649 }
650 do
651 s->fixed_coeffs[ch][end] = 0;
652 while (++end < 256);
653 }
654
655 /* zero the dithered coefficients for appropriate channels */
656 remove_dithering(s);
657 }
658
659 /**
660 * Stereo rematrixing.
661 * reference: Section 7.5.4 Rematrixing : Decoding Technique
662 */
do_rematrixing(AC3DecodeContext * s)663 static void do_rematrixing(AC3DecodeContext *s)
664 {
665 int bnd, i;
666 int end, bndend;
667
668 end = FFMIN(s->end_freq[1], s->end_freq[2]);
669
670 for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) {
671 if (s->rematrixing_flags[bnd]) {
672 bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd + 1]);
673 for (i = ff_ac3_rematrix_band_tab[bnd]; i < bndend; i++) {
674 int tmp0 = s->fixed_coeffs[1][i];
675 s->fixed_coeffs[1][i] += s->fixed_coeffs[2][i];
676 s->fixed_coeffs[2][i] = tmp0 - s->fixed_coeffs[2][i];
677 }
678 }
679 }
680 }
681
682 /**
683 * Inverse MDCT Transform.
684 * Convert frequency domain coefficients to time-domain audio samples.
685 * reference: Section 7.9.4 Transformation Equations
686 */
do_imdct(AC3DecodeContext * s,int channels,int offset)687 static inline void do_imdct(AC3DecodeContext *s, int channels, int offset)
688 {
689 int ch;
690
691 for (ch = 1; ch <= channels; ch++) {
692 if (s->block_switch[ch]) {
693 int i;
694 FFTSample *x = s->tmp_output + 128;
695 for (i = 0; i < 128; i++)
696 x[i] = s->transform_coeffs[ch][2 * i];
697 s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x);
698 #if USE_FIXED
699 s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1 + offset],
700 s->tmp_output, s->window, 128, 8);
701 #else
702 s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1 + offset],
703 s->tmp_output, s->window, 128);
704 #endif
705 for (i = 0; i < 128; i++)
706 x[i] = s->transform_coeffs[ch][2 * i + 1];
707 s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1 + offset], x);
708 } else {
709 s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
710 #if USE_FIXED
711 s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1 + offset],
712 s->tmp_output, s->window, 128, 8);
713 #else
714 s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1 + offset],
715 s->tmp_output, s->window, 128);
716 #endif
717 memcpy(s->delay[ch - 1 + offset], s->tmp_output + 128, 128 * sizeof(FFTSample));
718 }
719 }
720 }
721
722 /**
723 * Upmix delay samples from stereo to original channel layout.
724 */
ac3_upmix_delay(AC3DecodeContext * s)725 static void ac3_upmix_delay(AC3DecodeContext *s)
726 {
727 int channel_data_size = sizeof(s->delay[0]);
728 switch (s->channel_mode) {
729 case AC3_CHMODE_DUALMONO:
730 case AC3_CHMODE_STEREO:
731 /* upmix mono to stereo */
732 memcpy(s->delay[1], s->delay[0], channel_data_size);
733 break;
734 case AC3_CHMODE_2F2R:
735 memset(s->delay[3], 0, channel_data_size);
736 case AC3_CHMODE_2F1R:
737 memset(s->delay[2], 0, channel_data_size);
738 break;
739 case AC3_CHMODE_3F2R:
740 memset(s->delay[4], 0, channel_data_size);
741 case AC3_CHMODE_3F1R:
742 memset(s->delay[3], 0, channel_data_size);
743 case AC3_CHMODE_3F:
744 memcpy(s->delay[2], s->delay[1], channel_data_size);
745 memset(s->delay[1], 0, channel_data_size);
746 break;
747 }
748 }
749
750 /**
751 * Decode band structure for coupling, spectral extension, or enhanced coupling.
752 * The band structure defines how many subbands are in each band. For each
753 * subband in the range, 1 means it is combined with the previous band, and 0
754 * means that it starts a new band.
755 *
756 * @param[in] gbc bit reader context
757 * @param[in] blk block number
758 * @param[in] eac3 flag to indicate E-AC-3
759 * @param[in] ecpl flag to indicate enhanced coupling
760 * @param[in] start_subband subband number for start of range
761 * @param[in] end_subband subband number for end of range
762 * @param[in] default_band_struct default band structure table
763 * @param[out] num_bands number of bands (optionally NULL)
764 * @param[out] band_sizes array containing the number of bins in each band (optionally NULL)
765 * @param[in,out] band_struct current band structure
766 */
decode_band_structure(GetBitContext * gbc,int blk,int eac3,int ecpl,int start_subband,int end_subband,const uint8_t * default_band_struct,int * num_bands,uint8_t * band_sizes,uint8_t * band_struct,int band_struct_size)767 static void decode_band_structure(GetBitContext *gbc, int blk, int eac3,
768 int ecpl, int start_subband, int end_subband,
769 const uint8_t *default_band_struct,
770 int *num_bands, uint8_t *band_sizes,
771 uint8_t *band_struct, int band_struct_size)
772 {
773 int subbnd, bnd, n_subbands, n_bands=0;
774 uint8_t bnd_sz[22];
775
776 n_subbands = end_subband - start_subband;
777
778 if (!blk)
779 memcpy(band_struct, default_band_struct, band_struct_size);
780
781 av_assert0(band_struct_size >= start_subband + n_subbands);
782
783 band_struct += start_subband + 1;
784
785 /* decode band structure from bitstream or use default */
786 if (!eac3 || get_bits1(gbc)) {
787 for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) {
788 band_struct[subbnd] = get_bits1(gbc);
789 }
790 }
791
792 /* calculate number of bands and band sizes based on band structure.
793 note that the first 4 subbands in enhanced coupling span only 6 bins
794 instead of 12. */
795 if (num_bands || band_sizes ) {
796 n_bands = n_subbands;
797 bnd_sz[0] = ecpl ? 6 : 12;
798 for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) {
799 int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12;
800 if (band_struct[subbnd - 1]) {
801 n_bands--;
802 bnd_sz[bnd] += subbnd_size;
803 } else {
804 bnd_sz[++bnd] = subbnd_size;
805 }
806 }
807 }
808
809 /* set optional output params */
810 if (num_bands)
811 *num_bands = n_bands;
812 if (band_sizes)
813 memcpy(band_sizes, bnd_sz, n_bands);
814 }
815
spx_strategy(AC3DecodeContext * s,int blk)816 static inline int spx_strategy(AC3DecodeContext *s, int blk)
817 {
818 GetBitContext *bc = &s->gbc;
819 int fbw_channels = s->fbw_channels;
820 int dst_start_freq, dst_end_freq, src_start_freq,
821 start_subband, end_subband, ch;
822
823 /* determine which channels use spx */
824 if (s->channel_mode == AC3_CHMODE_MONO) {
825 s->channel_uses_spx[1] = 1;
826 } else {
827 for (ch = 1; ch <= fbw_channels; ch++)
828 s->channel_uses_spx[ch] = get_bits1(bc);
829 }
830
831 /* get the frequency bins of the spx copy region and the spx start
832 and end subbands */
833 dst_start_freq = get_bits(bc, 2);
834 start_subband = get_bits(bc, 3) + 2;
835 if (start_subband > 7)
836 start_subband += start_subband - 7;
837 end_subband = get_bits(bc, 3) + 5;
838 #if USE_FIXED
839 s->spx_dst_end_freq = end_freq_inv_tab[end_subband-5];
840 #endif
841 if (end_subband > 7)
842 end_subband += end_subband - 7;
843 dst_start_freq = dst_start_freq * 12 + 25;
844 src_start_freq = start_subband * 12 + 25;
845 dst_end_freq = end_subband * 12 + 25;
846
847 /* check validity of spx ranges */
848 if (start_subband >= end_subband) {
849 av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
850 "range (%d >= %d)\n", start_subband, end_subband);
851 return AVERROR_INVALIDDATA;
852 }
853 if (dst_start_freq >= src_start_freq) {
854 av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
855 "copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
856 return AVERROR_INVALIDDATA;
857 }
858
859 s->spx_dst_start_freq = dst_start_freq;
860 s->spx_src_start_freq = src_start_freq;
861 if (!USE_FIXED)
862 s->spx_dst_end_freq = dst_end_freq;
863
864 decode_band_structure(bc, blk, s->eac3, 0,
865 start_subband, end_subband,
866 ff_eac3_default_spx_band_struct,
867 &s->num_spx_bands,
868 s->spx_band_sizes,
869 s->spx_band_struct, sizeof(s->spx_band_struct));
870 return 0;
871 }
872
spx_coordinates(AC3DecodeContext * s)873 static inline void spx_coordinates(AC3DecodeContext *s)
874 {
875 GetBitContext *bc = &s->gbc;
876 int fbw_channels = s->fbw_channels;
877 int ch, bnd;
878
879 for (ch = 1; ch <= fbw_channels; ch++) {
880 if (s->channel_uses_spx[ch]) {
881 if (s->first_spx_coords[ch] || get_bits1(bc)) {
882 INTFLOAT spx_blend;
883 int bin, master_spx_coord;
884
885 s->first_spx_coords[ch] = 0;
886 spx_blend = AC3_SPX_BLEND(get_bits(bc, 5));
887 master_spx_coord = get_bits(bc, 2) * 3;
888
889 bin = s->spx_src_start_freq;
890 for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
891 int bandsize = s->spx_band_sizes[bnd];
892 int spx_coord_exp, spx_coord_mant;
893 INTFLOAT nratio, sblend, nblend;
894 #if USE_FIXED
895 /* calculate blending factors */
896 int64_t accu = ((bin << 23) + (bandsize << 22))
897 * (int64_t)s->spx_dst_end_freq;
898 nratio = (int)(accu >> 32);
899 nratio -= spx_blend << 18;
900
901 if (nratio < 0) {
902 nblend = 0;
903 sblend = 0x800000;
904 } else if (nratio > 0x7fffff) {
905 nblend = 14529495; // sqrt(3) in FP.23
906 sblend = 0;
907 } else {
908 nblend = fixed_sqrt(nratio, 23);
909 accu = (int64_t)nblend * 1859775393;
910 nblend = (int)((accu + (1<<29)) >> 30);
911 sblend = fixed_sqrt(0x800000 - nratio, 23);
912 }
913 #else
914 float spx_coord;
915
916 /* calculate blending factors */
917 nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend;
918 nratio = av_clipf(nratio, 0.0f, 1.0f);
919 nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
920 // to give unity variance
921 sblend = sqrtf(1.0f - nratio);
922 #endif
923 bin += bandsize;
924
925 /* decode spx coordinates */
926 spx_coord_exp = get_bits(bc, 4);
927 spx_coord_mant = get_bits(bc, 2);
928 if (spx_coord_exp == 15) spx_coord_mant <<= 1;
929 else spx_coord_mant += 4;
930 spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
931
932 /* multiply noise and signal blending factors by spx coordinate */
933 #if USE_FIXED
934 accu = (int64_t)nblend * spx_coord_mant;
935 s->spx_noise_blend[ch][bnd] = (int)((accu + (1<<22)) >> 23);
936 accu = (int64_t)sblend * spx_coord_mant;
937 s->spx_signal_blend[ch][bnd] = (int)((accu + (1<<22)) >> 23);
938 #else
939 spx_coord = spx_coord_mant * (1.0f / (1 << 23));
940 s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
941 s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
942 #endif
943 }
944 }
945 } else {
946 s->first_spx_coords[ch] = 1;
947 }
948 }
949 }
950
coupling_strategy(AC3DecodeContext * s,int blk,uint8_t * bit_alloc_stages)951 static inline int coupling_strategy(AC3DecodeContext *s, int blk,
952 uint8_t *bit_alloc_stages)
953 {
954 GetBitContext *bc = &s->gbc;
955 int fbw_channels = s->fbw_channels;
956 int channel_mode = s->channel_mode;
957 int ch;
958
959 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
960 if (!s->eac3)
961 s->cpl_in_use[blk] = get_bits1(bc);
962 if (s->cpl_in_use[blk]) {
963 /* coupling in use */
964 int cpl_start_subband, cpl_end_subband;
965
966 if (channel_mode < AC3_CHMODE_STEREO) {
967 av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
968 return AVERROR_INVALIDDATA;
969 }
970
971 /* check for enhanced coupling */
972 if (s->eac3 && get_bits1(bc)) {
973 /* TODO: parse enhanced coupling strategy info */
974 avpriv_request_sample(s->avctx, "Enhanced coupling");
975 return AVERROR_PATCHWELCOME;
976 }
977
978 /* determine which channels are coupled */
979 if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
980 s->channel_in_cpl[1] = 1;
981 s->channel_in_cpl[2] = 1;
982 } else {
983 for (ch = 1; ch <= fbw_channels; ch++)
984 s->channel_in_cpl[ch] = get_bits1(bc);
985 }
986
987 /* phase flags in use */
988 if (channel_mode == AC3_CHMODE_STEREO)
989 s->phase_flags_in_use = get_bits1(bc);
990
991 /* coupling frequency range */
992 cpl_start_subband = get_bits(bc, 4);
993 cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 :
994 get_bits(bc, 4) + 3;
995 if (cpl_start_subband >= cpl_end_subband) {
996 av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n",
997 cpl_start_subband, cpl_end_subband);
998 return AVERROR_INVALIDDATA;
999 }
1000 s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37;
1001 s->end_freq[CPL_CH] = cpl_end_subband * 12 + 37;
1002
1003 decode_band_structure(bc, blk, s->eac3, 0, cpl_start_subband,
1004 cpl_end_subband,
1005 ff_eac3_default_cpl_band_struct,
1006 &s->num_cpl_bands, s->cpl_band_sizes,
1007 s->cpl_band_struct, sizeof(s->cpl_band_struct));
1008 } else {
1009 /* coupling not in use */
1010 for (ch = 1; ch <= fbw_channels; ch++) {
1011 s->channel_in_cpl[ch] = 0;
1012 s->first_cpl_coords[ch] = 1;
1013 }
1014 s->first_cpl_leak = s->eac3;
1015 s->phase_flags_in_use = 0;
1016 }
1017
1018 return 0;
1019 }
1020
coupling_coordinates(AC3DecodeContext * s,int blk)1021 static inline int coupling_coordinates(AC3DecodeContext *s, int blk)
1022 {
1023 GetBitContext *bc = &s->gbc;
1024 int fbw_channels = s->fbw_channels;
1025 int ch, bnd;
1026 int cpl_coords_exist = 0;
1027
1028 for (ch = 1; ch <= fbw_channels; ch++) {
1029 if (s->channel_in_cpl[ch]) {
1030 if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(bc)) {
1031 int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
1032 s->first_cpl_coords[ch] = 0;
1033 cpl_coords_exist = 1;
1034 master_cpl_coord = 3 * get_bits(bc, 2);
1035 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
1036 cpl_coord_exp = get_bits(bc, 4);
1037 cpl_coord_mant = get_bits(bc, 4);
1038 if (cpl_coord_exp == 15)
1039 s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
1040 else
1041 s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
1042 s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
1043 }
1044 } else if (!blk) {
1045 av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must "
1046 "be present in block 0\n");
1047 return AVERROR_INVALIDDATA;
1048 }
1049 } else {
1050 /* channel not in coupling */
1051 s->first_cpl_coords[ch] = 1;
1052 }
1053 }
1054 /* phase flags */
1055 if (s->channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
1056 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
1057 s->phase_flags[bnd] = s->phase_flags_in_use ? get_bits1(bc) : 0;
1058 }
1059 }
1060
1061 return 0;
1062 }
1063
1064 /**
1065 * Decode a single audio block from the AC-3 bitstream.
1066 */
decode_audio_block(AC3DecodeContext * s,int blk,int offset)1067 static int decode_audio_block(AC3DecodeContext *s, int blk, int offset)
1068 {
1069 int fbw_channels = s->fbw_channels;
1070 int channel_mode = s->channel_mode;
1071 int i, bnd, seg, ch, ret;
1072 int different_transforms;
1073 int downmix_output;
1074 int cpl_in_use;
1075 GetBitContext *gbc = &s->gbc;
1076 uint8_t bit_alloc_stages[AC3_MAX_CHANNELS] = { 0 };
1077
1078 /* block switch flags */
1079 different_transforms = 0;
1080 if (s->block_switch_syntax) {
1081 for (ch = 1; ch <= fbw_channels; ch++) {
1082 s->block_switch[ch] = get_bits1(gbc);
1083 if (ch > 1 && s->block_switch[ch] != s->block_switch[1])
1084 different_transforms = 1;
1085 }
1086 }
1087
1088 /* dithering flags */
1089 if (s->dither_flag_syntax) {
1090 for (ch = 1; ch <= fbw_channels; ch++) {
1091 s->dither_flag[ch] = get_bits1(gbc);
1092 }
1093 }
1094
1095 /* dynamic range */
1096 i = !s->channel_mode;
1097 do {
1098 if (get_bits1(gbc)) {
1099 /* Allow asymmetric application of DRC when drc_scale > 1.
1100 Amplification of quiet sounds is enhanced */
1101 int range_bits = get_bits(gbc, 8);
1102 INTFLOAT range = AC3_RANGE(range_bits);
1103 if (range_bits <= 127 || s->drc_scale <= 1.0)
1104 s->dynamic_range[i] = AC3_DYNAMIC_RANGE(range);
1105 else
1106 s->dynamic_range[i] = range;
1107 } else if (blk == 0) {
1108 s->dynamic_range[i] = AC3_DYNAMIC_RANGE1;
1109 }
1110 } while (i--);
1111
1112 /* spectral extension strategy */
1113 if (s->eac3 && (!blk || get_bits1(gbc))) {
1114 s->spx_in_use = get_bits1(gbc);
1115 if (s->spx_in_use) {
1116 if ((ret = spx_strategy(s, blk)) < 0)
1117 return ret;
1118 }
1119 }
1120 if (!s->eac3 || !s->spx_in_use) {
1121 s->spx_in_use = 0;
1122 for (ch = 1; ch <= fbw_channels; ch++) {
1123 s->channel_uses_spx[ch] = 0;
1124 s->first_spx_coords[ch] = 1;
1125 }
1126 }
1127
1128 /* spectral extension coordinates */
1129 if (s->spx_in_use)
1130 spx_coordinates(s);
1131
1132 /* coupling strategy */
1133 if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
1134 if ((ret = coupling_strategy(s, blk, bit_alloc_stages)) < 0)
1135 return ret;
1136 } else if (!s->eac3) {
1137 if (!blk) {
1138 av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must "
1139 "be present in block 0\n");
1140 return AVERROR_INVALIDDATA;
1141 } else {
1142 s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
1143 }
1144 }
1145 cpl_in_use = s->cpl_in_use[blk];
1146
1147 /* coupling coordinates */
1148 if (cpl_in_use) {
1149 if ((ret = coupling_coordinates(s, blk)) < 0)
1150 return ret;
1151 }
1152
1153 /* stereo rematrixing strategy and band structure */
1154 if (channel_mode == AC3_CHMODE_STEREO) {
1155 if ((s->eac3 && !blk) || get_bits1(gbc)) {
1156 s->num_rematrixing_bands = 4;
1157 if (cpl_in_use && s->start_freq[CPL_CH] <= 61) {
1158 s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
1159 } else if (s->spx_in_use && s->spx_src_start_freq <= 61) {
1160 s->num_rematrixing_bands--;
1161 }
1162 for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++)
1163 s->rematrixing_flags[bnd] = get_bits1(gbc);
1164 } else if (!blk) {
1165 av_log(s->avctx, AV_LOG_WARNING, "Warning: "
1166 "new rematrixing strategy not present in block 0\n");
1167 s->num_rematrixing_bands = 0;
1168 }
1169 }
1170
1171 /* exponent strategies for each channel */
1172 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1173 if (!s->eac3)
1174 s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
1175 if (s->exp_strategy[blk][ch] != EXP_REUSE)
1176 bit_alloc_stages[ch] = 3;
1177 }
1178
1179 /* channel bandwidth */
1180 for (ch = 1; ch <= fbw_channels; ch++) {
1181 s->start_freq[ch] = 0;
1182 if (s->exp_strategy[blk][ch] != EXP_REUSE) {
1183 int group_size;
1184 int prev = s->end_freq[ch];
1185 if (s->channel_in_cpl[ch])
1186 s->end_freq[ch] = s->start_freq[CPL_CH];
1187 else if (s->channel_uses_spx[ch])
1188 s->end_freq[ch] = s->spx_src_start_freq;
1189 else {
1190 int bandwidth_code = get_bits(gbc, 6);
1191 if (bandwidth_code > 60) {
1192 av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code);
1193 return AVERROR_INVALIDDATA;
1194 }
1195 s->end_freq[ch] = bandwidth_code * 3 + 73;
1196 }
1197 group_size = 3 << (s->exp_strategy[blk][ch] - 1);
1198 s->num_exp_groups[ch] = (s->end_freq[ch] + group_size-4) / group_size;
1199 if (blk > 0 && s->end_freq[ch] != prev)
1200 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
1201 }
1202 }
1203 if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) {
1204 s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) /
1205 (3 << (s->exp_strategy[blk][CPL_CH] - 1));
1206 }
1207
1208 /* decode exponents for each channel */
1209 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1210 if (s->exp_strategy[blk][ch] != EXP_REUSE) {
1211 s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
1212 if (decode_exponents(s, gbc, s->exp_strategy[blk][ch],
1213 s->num_exp_groups[ch], s->dexps[ch][0],
1214 &s->dexps[ch][s->start_freq[ch]+!!ch])) {
1215 return AVERROR_INVALIDDATA;
1216 }
1217 if (ch != CPL_CH && ch != s->lfe_ch)
1218 skip_bits(gbc, 2); /* skip gainrng */
1219 }
1220 }
1221
1222 /* bit allocation information */
1223 if (s->bit_allocation_syntax) {
1224 if (get_bits1(gbc)) {
1225 s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
1226 s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
1227 s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
1228 s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
1229 s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
1230 for (ch = !cpl_in_use; ch <= s->channels; ch++)
1231 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1232 } else if (!blk) {
1233 av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must "
1234 "be present in block 0\n");
1235 return AVERROR_INVALIDDATA;
1236 }
1237 }
1238
1239 /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
1240 if (!s->eac3 || !blk) {
1241 if (s->snr_offset_strategy && get_bits1(gbc)) {
1242 int snr = 0;
1243 int csnr;
1244 csnr = (get_bits(gbc, 6) - 15) << 4;
1245 for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
1246 /* snr offset */
1247 if (ch == i || s->snr_offset_strategy == 2)
1248 snr = (csnr + get_bits(gbc, 4)) << 2;
1249 /* run at least last bit allocation stage if snr offset changes */
1250 if (blk && s->snr_offset[ch] != snr) {
1251 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
1252 }
1253 s->snr_offset[ch] = snr;
1254
1255 /* fast gain (normal AC-3 only) */
1256 if (!s->eac3) {
1257 int prev = s->fast_gain[ch];
1258 s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
1259 /* run last 2 bit allocation stages if fast gain changes */
1260 if (blk && prev != s->fast_gain[ch])
1261 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1262 }
1263 }
1264 } else if (!s->eac3 && !blk) {
1265 av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
1266 return AVERROR_INVALIDDATA;
1267 }
1268 }
1269
1270 /* fast gain (E-AC-3 only) */
1271 if (s->fast_gain_syntax && get_bits1(gbc)) {
1272 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1273 int prev = s->fast_gain[ch];
1274 s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
1275 /* run last 2 bit allocation stages if fast gain changes */
1276 if (blk && prev != s->fast_gain[ch])
1277 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1278 }
1279 } else if (s->eac3 && !blk) {
1280 for (ch = !cpl_in_use; ch <= s->channels; ch++)
1281 s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
1282 }
1283
1284 /* E-AC-3 to AC-3 converter SNR offset */
1285 if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
1286 skip_bits(gbc, 10); // skip converter snr offset
1287 }
1288
1289 /* coupling leak information */
1290 if (cpl_in_use) {
1291 if (s->first_cpl_leak || get_bits1(gbc)) {
1292 int fl = get_bits(gbc, 3);
1293 int sl = get_bits(gbc, 3);
1294 /* run last 2 bit allocation stages for coupling channel if
1295 coupling leak changes */
1296 if (blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
1297 sl != s->bit_alloc_params.cpl_slow_leak)) {
1298 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
1299 }
1300 s->bit_alloc_params.cpl_fast_leak = fl;
1301 s->bit_alloc_params.cpl_slow_leak = sl;
1302 } else if (!s->eac3 && !blk) {
1303 av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must "
1304 "be present in block 0\n");
1305 return AVERROR_INVALIDDATA;
1306 }
1307 s->first_cpl_leak = 0;
1308 }
1309
1310 /* delta bit allocation information */
1311 if (s->dba_syntax && get_bits1(gbc)) {
1312 /* delta bit allocation exists (strategy) */
1313 for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
1314 s->dba_mode[ch] = get_bits(gbc, 2);
1315 if (s->dba_mode[ch] == DBA_RESERVED) {
1316 av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
1317 return AVERROR_INVALIDDATA;
1318 }
1319 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1320 }
1321 /* channel delta offset, len and bit allocation */
1322 for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
1323 if (s->dba_mode[ch] == DBA_NEW) {
1324 s->dba_nsegs[ch] = get_bits(gbc, 3) + 1;
1325 for (seg = 0; seg < s->dba_nsegs[ch]; seg++) {
1326 s->dba_offsets[ch][seg] = get_bits(gbc, 5);
1327 s->dba_lengths[ch][seg] = get_bits(gbc, 4);
1328 s->dba_values[ch][seg] = get_bits(gbc, 3);
1329 }
1330 /* run last 2 bit allocation stages if new dba values */
1331 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
1332 }
1333 }
1334 } else if (blk == 0) {
1335 for (ch = 0; ch <= s->channels; ch++) {
1336 s->dba_mode[ch] = DBA_NONE;
1337 }
1338 }
1339
1340 /* Bit allocation */
1341 for (ch = !cpl_in_use; ch <= s->channels; ch++) {
1342 if (bit_alloc_stages[ch] > 2) {
1343 /* Exponent mapping into PSD and PSD integration */
1344 ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
1345 s->start_freq[ch], s->end_freq[ch],
1346 s->psd[ch], s->band_psd[ch]);
1347 }
1348 if (bit_alloc_stages[ch] > 1) {
1349 /* Compute excitation function, Compute masking curve, and
1350 Apply delta bit allocation */
1351 if (ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
1352 s->start_freq[ch], s->end_freq[ch],
1353 s->fast_gain[ch], (ch == s->lfe_ch),
1354 s->dba_mode[ch], s->dba_nsegs[ch],
1355 s->dba_offsets[ch], s->dba_lengths[ch],
1356 s->dba_values[ch], s->mask[ch])) {
1357 av_log(s->avctx, AV_LOG_ERROR, "error in bit allocation\n");
1358 return AVERROR_INVALIDDATA;
1359 }
1360 }
1361 if (bit_alloc_stages[ch] > 0) {
1362 /* Compute bit allocation */
1363 const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
1364 ff_eac3_hebap_tab : ff_ac3_bap_tab;
1365 s->ac3dsp.bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
1366 s->start_freq[ch], s->end_freq[ch],
1367 s->snr_offset[ch],
1368 s->bit_alloc_params.floor,
1369 bap_tab, s->bap[ch]);
1370 }
1371 }
1372
1373 /* unused dummy data */
1374 if (s->skip_syntax && get_bits1(gbc)) {
1375 int skipl = get_bits(gbc, 9);
1376 skip_bits_long(gbc, 8 * skipl);
1377 }
1378
1379 /* unpack the transform coefficients
1380 this also uncouples channels if coupling is in use. */
1381 decode_transform_coeffs(s, blk);
1382
1383 /* TODO: generate enhanced coupling coordinates and uncouple */
1384
1385 /* recover coefficients if rematrixing is in use */
1386 if (s->channel_mode == AC3_CHMODE_STEREO)
1387 do_rematrixing(s);
1388
1389 /* apply scaling to coefficients (headroom, dynrng) */
1390 for (ch = 1; ch <= s->channels; ch++) {
1391 int audio_channel = 0;
1392 INTFLOAT gain;
1393 if (s->channel_mode == AC3_CHMODE_DUALMONO && ch <= 2)
1394 audio_channel = 2-ch;
1395 if (s->heavy_compression && s->compression_exists[audio_channel])
1396 gain = s->heavy_dynamic_range[audio_channel];
1397 else
1398 gain = s->dynamic_range[audio_channel];
1399
1400 #if USE_FIXED
1401 scale_coefs(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
1402 #else
1403 if (s->target_level != 0)
1404 gain = gain * s->level_gain[audio_channel];
1405 gain *= 1.0 / 4194304.0f;
1406 s->fmt_conv.int32_to_float_fmul_scalar(s->transform_coeffs[ch],
1407 s->fixed_coeffs[ch], gain, 256);
1408 #endif
1409 }
1410
1411 /* apply spectral extension to high frequency bins */
1412 if (CONFIG_EAC3_DECODER && s->spx_in_use) {
1413 ff_eac3_apply_spectral_extension(s);
1414 }
1415
1416 /* downmix and MDCT. order depends on whether block switching is used for
1417 any channel in this block. this is because coefficients for the long
1418 and short transforms cannot be mixed. */
1419 downmix_output = s->channels != s->out_channels &&
1420 !((s->output_mode & AC3_OUTPUT_LFEON) &&
1421 s->fbw_channels == s->out_channels);
1422 if (different_transforms) {
1423 /* the delay samples have already been downmixed, so we upmix the delay
1424 samples in order to reconstruct all channels before downmixing. */
1425 if (s->downmixed) {
1426 s->downmixed = 0;
1427 ac3_upmix_delay(s);
1428 }
1429
1430 do_imdct(s, s->channels, offset);
1431
1432 if (downmix_output) {
1433 #if USE_FIXED
1434 ac3_downmix_c_fixed16(s->outptr, s->downmix_coeffs,
1435 s->out_channels, s->fbw_channels, 256);
1436 #else
1437 ff_ac3dsp_downmix(&s->ac3dsp, s->outptr, s->downmix_coeffs,
1438 s->out_channels, s->fbw_channels, 256);
1439 #endif
1440 }
1441 } else {
1442 if (downmix_output) {
1443 AC3_RENAME(ff_ac3dsp_downmix)(&s->ac3dsp, s->xcfptr + 1, s->downmix_coeffs,
1444 s->out_channels, s->fbw_channels, 256);
1445 }
1446
1447 if (downmix_output && !s->downmixed) {
1448 s->downmixed = 1;
1449 AC3_RENAME(ff_ac3dsp_downmix)(&s->ac3dsp, s->dlyptr, s->downmix_coeffs,
1450 s->out_channels, s->fbw_channels, 128);
1451 }
1452
1453 do_imdct(s, s->out_channels, offset);
1454 }
1455
1456 return 0;
1457 }
1458
1459 /**
1460 * Decode a single AC-3 frame.
1461 */
ac3_decode_frame(AVCodecContext * avctx,void * data,int * got_frame_ptr,AVPacket * avpkt)1462 static int ac3_decode_frame(AVCodecContext * avctx, void *data,
1463 int *got_frame_ptr, AVPacket *avpkt)
1464 {
1465 AVFrame *frame = data;
1466 const uint8_t *buf = avpkt->data;
1467 int buf_size, full_buf_size = avpkt->size;
1468 AC3DecodeContext *s = avctx->priv_data;
1469 int blk, ch, err, offset, ret;
1470 int i;
1471 int skip = 0, got_independent_frame = 0;
1472 const uint8_t *channel_map;
1473 uint8_t extended_channel_map[EAC3_MAX_CHANNELS];
1474 const SHORTFLOAT *output[AC3_MAX_CHANNELS];
1475 enum AVMatrixEncoding matrix_encoding;
1476 AVDownmixInfo *downmix_info;
1477
1478 s->superframe_size = 0;
1479
1480 buf_size = full_buf_size;
1481 for (i = 1; i < buf_size; i += 2) {
1482 if (buf[i] == 0x77 || buf[i] == 0x0B) {
1483 if ((buf[i] ^ buf[i-1]) == (0x77 ^ 0x0B)) {
1484 i--;
1485 break;
1486 } else if ((buf[i] ^ buf[i+1]) == (0x77 ^ 0x0B)) {
1487 break;
1488 }
1489 }
1490 }
1491 if (i >= buf_size)
1492 return AVERROR_INVALIDDATA;
1493 if (i > 10)
1494 return i;
1495 buf += i;
1496 buf_size -= i;
1497
1498 /* copy input buffer to decoder context to avoid reading past the end
1499 of the buffer, which can be caused by a damaged input stream. */
1500 if (buf_size >= 2 && AV_RB16(buf) == 0x770B) {
1501 // seems to be byte-swapped AC-3
1502 int cnt = FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE) >> 1;
1503 s->bdsp.bswap16_buf((uint16_t *) s->input_buffer,
1504 (const uint16_t *) buf, cnt);
1505 } else
1506 memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
1507
1508 /* if consistent noise generation is enabled, seed the linear feedback generator
1509 * with the contents of the AC-3 frame so that the noise is identical across
1510 * decodes given the same AC-3 frame data, for use with non-linear edititing software. */
1511 if (s->consistent_noise_generation)
1512 av_lfg_init_from_data(&s->dith_state, s->input_buffer, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
1513
1514 buf = s->input_buffer;
1515 dependent_frame:
1516 /* initialize the GetBitContext with the start of valid AC-3 Frame */
1517 if ((ret = init_get_bits8(&s->gbc, buf, buf_size)) < 0)
1518 return ret;
1519
1520 /* parse the syncinfo */
1521 err = parse_frame_header(s);
1522
1523 if (err) {
1524 switch (err) {
1525 case AAC_AC3_PARSE_ERROR_SYNC:
1526 av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
1527 return AVERROR_INVALIDDATA;
1528 case AAC_AC3_PARSE_ERROR_BSID:
1529 av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
1530 break;
1531 case AAC_AC3_PARSE_ERROR_SAMPLE_RATE:
1532 av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
1533 break;
1534 case AAC_AC3_PARSE_ERROR_FRAME_SIZE:
1535 av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
1536 break;
1537 case AAC_AC3_PARSE_ERROR_FRAME_TYPE:
1538 /* skip frame if CRC is ok. otherwise use error concealment. */
1539 /* TODO: add support for substreams */
1540 if (s->substreamid) {
1541 av_log(avctx, AV_LOG_DEBUG,
1542 "unsupported substream %d: skipping frame\n",
1543 s->substreamid);
1544 *got_frame_ptr = 0;
1545 return buf_size;
1546 } else {
1547 av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
1548 }
1549 break;
1550 case AAC_AC3_PARSE_ERROR_CRC:
1551 case AAC_AC3_PARSE_ERROR_CHANNEL_CFG:
1552 break;
1553 default: // Normal AVERROR do not try to recover.
1554 *got_frame_ptr = 0;
1555 return err;
1556 }
1557 } else {
1558 /* check that reported frame size fits in input buffer */
1559 if (s->frame_size > buf_size) {
1560 av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
1561 err = AAC_AC3_PARSE_ERROR_FRAME_SIZE;
1562 } else if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
1563 /* check for crc mismatch */
1564 if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2],
1565 s->frame_size - 2)) {
1566 av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
1567 if (avctx->err_recognition & AV_EF_EXPLODE)
1568 return AVERROR_INVALIDDATA;
1569 err = AAC_AC3_PARSE_ERROR_CRC;
1570 }
1571 }
1572 }
1573
1574 if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT && !got_independent_frame) {
1575 av_log(avctx, AV_LOG_WARNING, "Ignoring dependent frame without independent frame.\n");
1576 *got_frame_ptr = 0;
1577 return FFMIN(full_buf_size, s->frame_size);
1578 }
1579
1580 /* channel config */
1581 if (!err || (s->channels && s->out_channels != s->channels)) {
1582 s->out_channels = s->channels;
1583 s->output_mode = s->channel_mode;
1584 if (s->lfe_on)
1585 s->output_mode |= AC3_OUTPUT_LFEON;
1586 if (s->channels > 1 &&
1587 avctx->request_channel_layout == AV_CH_LAYOUT_MONO) {
1588 s->out_channels = 1;
1589 s->output_mode = AC3_CHMODE_MONO;
1590 } else if (s->channels > 2 &&
1591 avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {
1592 s->out_channels = 2;
1593 s->output_mode = AC3_CHMODE_STEREO;
1594 }
1595
1596 s->loro_center_mix_level = gain_levels[s-> center_mix_level];
1597 s->loro_surround_mix_level = gain_levels[s->surround_mix_level];
1598 s->ltrt_center_mix_level = LEVEL_MINUS_3DB;
1599 s->ltrt_surround_mix_level = LEVEL_MINUS_3DB;
1600 /* set downmixing coefficients if needed */
1601 if (s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
1602 s->fbw_channels == s->out_channels)) {
1603 if ((ret = set_downmix_coeffs(s)) < 0) {
1604 av_log(avctx, AV_LOG_ERROR, "error setting downmix coeffs\n");
1605 return ret;
1606 }
1607 }
1608 } else if (!s->channels) {
1609 av_log(avctx, AV_LOG_ERROR, "unable to determine channel mode\n");
1610 return AVERROR_INVALIDDATA;
1611 }
1612 avctx->channels = s->out_channels;
1613 avctx->channel_layout = avpriv_ac3_channel_layout_tab[s->output_mode & ~AC3_OUTPUT_LFEON];
1614 if (s->output_mode & AC3_OUTPUT_LFEON)
1615 avctx->channel_layout |= AV_CH_LOW_FREQUENCY;
1616
1617 /* set audio service type based on bitstream mode for AC-3 */
1618 avctx->audio_service_type = s->bitstream_mode;
1619 if (s->bitstream_mode == 0x7 && s->channels > 1)
1620 avctx->audio_service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
1621
1622 /* decode the audio blocks */
1623 channel_map = ff_ac3_dec_channel_map[s->output_mode & ~AC3_OUTPUT_LFEON][s->lfe_on];
1624 offset = s->frame_type == EAC3_FRAME_TYPE_DEPENDENT ? AC3_MAX_CHANNELS : 0;
1625 for (ch = 0; ch < AC3_MAX_CHANNELS; ch++) {
1626 output[ch] = s->output[ch + offset];
1627 s->outptr[ch] = s->output[ch + offset];
1628 }
1629 for (ch = 0; ch < s->channels; ch++) {
1630 if (ch < s->out_channels)
1631 s->outptr[channel_map[ch]] = s->output_buffer[ch + offset];
1632 }
1633 for (blk = 0; blk < s->num_blocks; blk++) {
1634 if (!err && decode_audio_block(s, blk, offset)) {
1635 av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
1636 err = 1;
1637 }
1638 if (err)
1639 for (ch = 0; ch < s->out_channels; ch++)
1640 memcpy(s->output_buffer[ch + offset] + AC3_BLOCK_SIZE*blk, output[ch], AC3_BLOCK_SIZE*sizeof(SHORTFLOAT));
1641 for (ch = 0; ch < s->out_channels; ch++)
1642 output[ch] = s->outptr[channel_map[ch]];
1643 for (ch = 0; ch < s->out_channels; ch++) {
1644 if (!ch || channel_map[ch])
1645 s->outptr[channel_map[ch]] += AC3_BLOCK_SIZE;
1646 }
1647 }
1648
1649 /* keep last block for error concealment in next frame */
1650 for (ch = 0; ch < s->out_channels; ch++)
1651 memcpy(s->output[ch + offset], output[ch], AC3_BLOCK_SIZE*sizeof(SHORTFLOAT));
1652
1653 /* check if there is dependent frame */
1654 if (buf_size > s->frame_size) {
1655 AC3HeaderInfo hdr;
1656 int err;
1657
1658 if (buf_size - s->frame_size <= 16) {
1659 skip = buf_size - s->frame_size;
1660 goto skip;
1661 }
1662
1663 if ((ret = init_get_bits8(&s->gbc, buf + s->frame_size, buf_size - s->frame_size)) < 0)
1664 return ret;
1665
1666 err = ff_ac3_parse_header(&s->gbc, &hdr);
1667 if (err)
1668 return err;
1669
1670 if (hdr.frame_type == EAC3_FRAME_TYPE_DEPENDENT) {
1671 if (hdr.num_blocks != s->num_blocks || s->sample_rate != hdr.sample_rate) {
1672 av_log(avctx, AV_LOG_WARNING, "Ignoring non-compatible dependent frame.\n");
1673 } else {
1674 buf += s->frame_size;
1675 buf_size -= s->frame_size;
1676 s->prev_output_mode = s->output_mode;
1677 s->prev_bit_rate = s->bit_rate;
1678 got_independent_frame = 1;
1679 goto dependent_frame;
1680 }
1681 }
1682 }
1683 skip:
1684
1685 frame->decode_error_flags = err ? FF_DECODE_ERROR_INVALID_BITSTREAM : 0;
1686
1687 /* if frame is ok, set audio parameters */
1688 if (!err) {
1689 avctx->sample_rate = s->sample_rate;
1690 avctx->bit_rate = s->bit_rate + s->prev_bit_rate;
1691 }
1692
1693 for (ch = 0; ch < EAC3_MAX_CHANNELS; ch++)
1694 extended_channel_map[ch] = ch;
1695
1696 if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT) {
1697 uint64_t ich_layout = avpriv_ac3_channel_layout_tab[s->prev_output_mode & ~AC3_OUTPUT_LFEON];
1698 int channel_map_size = ff_ac3_channels_tab[s->output_mode & ~AC3_OUTPUT_LFEON] + s->lfe_on;
1699 uint64_t channel_layout;
1700 int extend = 0;
1701
1702 if (s->prev_output_mode & AC3_OUTPUT_LFEON)
1703 ich_layout |= AV_CH_LOW_FREQUENCY;
1704
1705 channel_layout = ich_layout;
1706 for (ch = 0; ch < 16; ch++) {
1707 if (s->channel_map & (1 << (EAC3_MAX_CHANNELS - ch - 1))) {
1708 channel_layout |= ff_eac3_custom_channel_map_locations[ch][1];
1709 }
1710 }
1711 if (av_get_channel_layout_nb_channels(channel_layout) > EAC3_MAX_CHANNELS) {
1712 av_log(avctx, AV_LOG_ERROR, "Too many channels (%d) coded\n",
1713 av_get_channel_layout_nb_channels(channel_layout));
1714 return AVERROR_INVALIDDATA;
1715 }
1716
1717 avctx->channel_layout = channel_layout;
1718 avctx->channels = av_get_channel_layout_nb_channels(channel_layout);
1719
1720 for (ch = 0; ch < EAC3_MAX_CHANNELS; ch++) {
1721 if (s->channel_map & (1 << (EAC3_MAX_CHANNELS - ch - 1))) {
1722 if (ff_eac3_custom_channel_map_locations[ch][0]) {
1723 int index = av_get_channel_layout_channel_index(channel_layout,
1724 ff_eac3_custom_channel_map_locations[ch][1]);
1725 if (index < 0)
1726 return AVERROR_INVALIDDATA;
1727 if (extend >= channel_map_size)
1728 return AVERROR_INVALIDDATA;
1729
1730 extended_channel_map[index] = offset + channel_map[extend++];
1731 } else {
1732 int i;
1733
1734 for (i = 0; i < 64; i++) {
1735 if ((1ULL << i) & ff_eac3_custom_channel_map_locations[ch][1]) {
1736 int index = av_get_channel_layout_channel_index(channel_layout,
1737 1ULL << i);
1738 if (index < 0)
1739 return AVERROR_INVALIDDATA;
1740 if (extend >= channel_map_size)
1741 return AVERROR_INVALIDDATA;
1742
1743 extended_channel_map[index] = offset + channel_map[extend++];
1744 }
1745 }
1746 }
1747 }
1748 }
1749 }
1750
1751 /* get output buffer */
1752 frame->nb_samples = s->num_blocks * AC3_BLOCK_SIZE;
1753 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1754 return ret;
1755
1756 for (ch = 0; ch < avctx->channels; ch++) {
1757 int map = extended_channel_map[ch];
1758 av_assert0(ch>=AV_NUM_DATA_POINTERS || frame->extended_data[ch] == frame->data[ch]);
1759 memcpy((SHORTFLOAT *)frame->extended_data[ch],
1760 s->output_buffer[map],
1761 s->num_blocks * AC3_BLOCK_SIZE * sizeof(SHORTFLOAT));
1762 }
1763
1764 /*
1765 * AVMatrixEncoding
1766 *
1767 * Check whether the input layout is compatible, and make sure we're not
1768 * downmixing (else the matrix encoding is no longer applicable).
1769 */
1770 matrix_encoding = AV_MATRIX_ENCODING_NONE;
1771 if (s->channel_mode == AC3_CHMODE_STEREO &&
1772 s->channel_mode == (s->output_mode & ~AC3_OUTPUT_LFEON)) {
1773 if (s->dolby_surround_mode == AC3_DSURMOD_ON)
1774 matrix_encoding = AV_MATRIX_ENCODING_DOLBY;
1775 else if (s->dolby_headphone_mode == AC3_DHEADPHONMOD_ON)
1776 matrix_encoding = AV_MATRIX_ENCODING_DOLBYHEADPHONE;
1777 } else if (s->channel_mode >= AC3_CHMODE_2F2R &&
1778 s->channel_mode == (s->output_mode & ~AC3_OUTPUT_LFEON)) {
1779 switch (s->dolby_surround_ex_mode) {
1780 case AC3_DSUREXMOD_ON: // EX or PLIIx
1781 matrix_encoding = AV_MATRIX_ENCODING_DOLBYEX;
1782 break;
1783 case AC3_DSUREXMOD_PLIIZ:
1784 matrix_encoding = AV_MATRIX_ENCODING_DPLIIZ;
1785 break;
1786 default: // not indicated or off
1787 break;
1788 }
1789 }
1790 if ((ret = ff_side_data_update_matrix_encoding(frame, matrix_encoding)) < 0)
1791 return ret;
1792
1793 /* AVDownmixInfo */
1794 if ((downmix_info = av_downmix_info_update_side_data(frame))) {
1795 switch (s->preferred_downmix) {
1796 case AC3_DMIXMOD_LTRT:
1797 downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LTRT;
1798 break;
1799 case AC3_DMIXMOD_LORO:
1800 downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LORO;
1801 break;
1802 case AC3_DMIXMOD_DPLII:
1803 downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_DPLII;
1804 break;
1805 default:
1806 downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_UNKNOWN;
1807 break;
1808 }
1809 downmix_info->center_mix_level = gain_levels[s-> center_mix_level];
1810 downmix_info->center_mix_level_ltrt = gain_levels[s-> center_mix_level_ltrt];
1811 downmix_info->surround_mix_level = gain_levels[s-> surround_mix_level];
1812 downmix_info->surround_mix_level_ltrt = gain_levels[s->surround_mix_level_ltrt];
1813 if (s->lfe_mix_level_exists)
1814 downmix_info->lfe_mix_level = gain_levels_lfe[s->lfe_mix_level];
1815 else
1816 downmix_info->lfe_mix_level = 0.0; // -inf dB
1817 } else
1818 return AVERROR(ENOMEM);
1819
1820 *got_frame_ptr = 1;
1821
1822 if (!s->superframe_size)
1823 return FFMIN(full_buf_size, s->frame_size + skip);
1824
1825 return FFMIN(full_buf_size, s->superframe_size + skip);
1826 }
1827
1828 /**
1829 * Uninitialize the AC-3 decoder.
1830 */
ac3_decode_end(AVCodecContext * avctx)1831 static av_cold int ac3_decode_end(AVCodecContext *avctx)
1832 {
1833 AC3DecodeContext *s = avctx->priv_data;
1834 ff_mdct_end(&s->imdct_512);
1835 ff_mdct_end(&s->imdct_256);
1836 av_freep(&s->fdsp);
1837 av_freep(&s->downmix_coeffs[0]);
1838
1839 return 0;
1840 }
1841
1842 #define OFFSET(x) offsetof(AC3DecodeContext, x)
1843 #define PAR (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM)
1844